Nokia explains how wireless charging works in Lumia Windows Phones

Nokia has published an in-depth article over on its Conversations blog detailing how wireless charging works in its latest Lumia Windows Phones. Both the Lumia 820 (with compatible back plates) and Lumia 920 support wireless charging by simply resting on a compatible charging plate, Fatboy Pillow, or even a speaker such as the JBL PowerUp entertainment system.

Using Qi standards, Nokia is able to allow consumers make use of accessories to achieve impressive results. Gone will be the days of hunting through the mess of cables for the USB adapter, for then to locate a free socket and to then fiddle with the device to connect it to a mains or PC. But just how does wireless charging work?

Wireless charging, as anyone could imagine, is the method of transmitting energy through air to a receiving surface - a smartphone in this case. Instead of power travelling through the attached USB cable, consumers will be able to simply rest either the Lumia 820 or Lumia 920 on a compatible charging station, which will then activate the process. Neat, eh?

Wireless Charging Process

The above diagram illustrates what's involved, and the Nokia article explains it perfectly:

"A transmitter coil is positioned at the bottom (L1) and the receiver coil (L2) is situated at the top and these coils are embedded into different electrical devices. L1 would be the Nokia Wireless Charging Plate and L2 would be the Nokia Lumia 920, for example."

As mentioned above, Nokia makes use of the Qi standard in wireless charging. Qi was created by the Wireless Power Consortium and is reportedly used by over 100 different companies across the globe. This means compatibility with other charging means is possible with Lumia Windows Phone hardware.

Nokia has already formed partnerships with Coffee Bean, Tea Leaf, and Virgin Atlantic, that will each allow Lumia 820 and Lumia 920 owners to charge devices using table-top charging stations.

For those who find themselves at home or in the office, Nokia will be offering a number of accessories to be used with Lumia Windows Phones to achieve similar results. The Nokia charging plate, Fatboy Pillow and JBL PowerUp speakers name but a few. Nokia has stated these products will be available from all popular retailers.

Source: Nokia Conversations

Rich Edmonds
Senior Editor, PC Build

Rich Edmonds was formerly a Senior Editor of PC hardware at Windows Central, covering everything related to PC components and NAS. He's been involved in technology for more than a decade and knows a thing or two about the magic inside a PC chassis. You can follow him on Twitter at @RichEdmonds.

  • Wonder if it will work with a touchstone :P
  • Yeah would love to be able to recycle mine with a 920...
  • Is' it a Qi standard charger ? If so, It will work
  • Its not that's why I'm curious
  • I am wondering the same thing.  I would love to use it with my Touchstone 2 with audio dock.  Otherwise, some lucky ebayer will get the extremely rare device.
  • Phones are supposedly the dirtiest thing we have, I don't think I'll be using these charging pads in airports and coffee shops. Great visibility though, like Tesla's Supercharger. This is will be great around the home though. Gonna get many a pillow.
  • The fronts of phones are, but I see no difference in putting your phone down on a wireless charger than a's the same thing.
  • But that is why we have immune system in the first place. Please don't get me wrong. Being clean is good but dont be overcautious about things.
  • +1
  • Come on give us a +1 button or Like button.We need them.
  • +1
  • Also, WPCEntral keeps using that picture of a Lumia on a wooden table where the charger is UNDER the primary surface.  I see that becoming the standard pretty quickly, meaning that it will all be one surface that is easy to wipe down and keep clean.  I do not think germs would be a problem anyway, it isn't like you go around licking your phone, and these chargers will be just as dirty as a door handle.
  • I'm not a germaphobe by any means, my phone just stays in my pocket more often then out when I'm not home. One reason because tables are sticky or dirty or wet or moist or or or... My home will have four pillows throughout and three phones that will use them...speaking of that, is there a negative effect of more than one phone on a mat? Like slower charges?
  • It might not work at all if it puts the coils (and magnetic fields) too far out of alignment.
  • I just keep a box of those little alcohol swabs on my desk and wipe it down every morning, a box is like $3 at Rite Aid
  • Very cool feature. Another reason Nokia will probably sell a lot of phones.
  • Yes, among the other amazing features, and the much less innovative Iphone 5 (awww too soon?)
  • Does anyone know can these charges work through things ? I would like to get some QI chargers and build them into things (pulling it out of the OEM case and mounting them under items) so I can just drop my 920 (as long as VZW gets it) on my nightstand (for example) and it just start charging...
    Do they work from an inch from the charger or more ?
  • The coils can be put into things, sure. We saw tables at the Nokia event that were just giant tables, but an area was marked off in tape where the coils were. When the phone was placed in that exact spot, it charged. I imagine you can very much DIY these things. As to how much "stuff" can be in the way, I have no idea.
  • I was reading about the standard a bit ago, and paperwork seemed to say that Qi Chargers would work up to about 1 inch away.  I imagine that was a number with the device hanging above a charger, but it didn't I'd assume it would have no problem going through a quarter inch of wood.
    EDIT: Engaget has an article, it is good up to 40mm.
  • thanks for that post. I picked up one of the energizer ones from ebay for $16. I might try to grab another one or 2 (under $20). I'll gut the case and mount it under tables and things. It has a 2 charger station, so it will make the range a little better. 
    I want to put one in my nightstand so I dont have to fumble looking for a cable like I have to do every night before going to bed (mount right below)
    I wonder what the loss is over a longer rannge... Do you lose like 10 of charging speed for being a distance away ? (like wi-fi, less bars, lower speed)
    This is awsome news tho. Do they have to be 100% in spot or is it flexable with a little space ?
  • I don't know how these are constructed on the inside, ie how moddable they are, but to increase the range you'd want to increase the current. Again, I haven't seen the inside of one and a small current increase may fry it. If it's simple enough you may even be able to make your own...
  • It looks like the Qi standard is good for 5 watts, so that should be 1 amp at USB voltage (5V). Take your battery size and calculate from there. A 3500mAh battery would take 3.5 hours to charge.
  • 1 amp is pretty much what a standard wall charger supplies, but 3500mAh? I think you confused a phone battery with a laptope one.
  • Haha yeah, it's just the first size that came to mind (the galaxy note is actually getting a 3100mAh battery). What's the lumia 920 going to be, 1800mAh?
  • The 800 got a 1450mAh, the 900 a 1820mAh, and the 920 is supposed to get a 2000mAh battery. Quite large but still reasonable compared to the Galaxy Board.
  • Pre and hp touchpad worked In cases as long as it's not like an otterbox should be fine
  • What about transferring of data?  I assume I'll still need the USB cable if I move data to and from my phone?
  • Wireless syncing like Zune already does.
  • Wireless syncing. I suppose if you need to do a quick sync, a USB cable would work, but if you are charging your phone, then wireless syncing (which WP7 already does) should work just fine.
  • As long as you don't have wait 10 minutes for the wireless sync to start,j ust do it manually
  • Interesting technology but still a big question remains: how long does the charging take?
  • This is a good question, is there any documented compaired to USB charging ?
  • I read that wireless charging would take somewhere about 3 hours against wired charging 2.5 hours so it's pretty neat if you ask me!
  • The russian guys who made the camera comparison videos stated that charging would take that long.
  • I replied to an earlier post about charging time, I think I meant to reply to this one. I'm using the wpcentral app so I can't copy my response.
  • You left out the important paragraph that mentions the induction.
  • I bought two Energizer Dual Charging stations on Amazon (under $20 each) so my wife and I can charge at the same time.  Now we just need the phones!  Can't hardly wait!
  • Is it magnetized? The palm touchstone was and it was great for car applications.
  • Nope. It's really disappointing and sort of completely ruins the whole "simple" aspect.  Without a magnet, how do I center it?  I need to line it up with tiny lines printed on the thing... ugh.  What was great about the palm was being able to charge my phone without thinking.  Just set it down.  Now I still need to think, look, line things up.  Not a hassle per say, but nearly as elegant a solution.
    Source: I was at the release party and played with the phones/chargers.
  • I have an energizer wireless charger for the wii, maybe I can pickup wii remote and set down phone, they can share. Not sure if it's qi though.
  • The wii energizer charger isn't Qi compatible, they used there own tech on that one.
  • I'm happy to see this. I just wonder why it took so long. My toothbrush charged this way 15 years ago.
  • in future Nokia wireless charging will charge you too XD
  • All this wireless technology makes me think, what would have happened if Tesla actually perfected his giant Tesla coil in NY. Wonder where we'd be today. Btw you can thank him for a lot of tech we have today. Remember who invented AC current (discovered it it is a better word).
  • Agreed. If Edison hadn't tried to ruin him and if he'd been a bit less reclusive and written more things down... A true genius.
  • Is the powermat (before the Duracell partnership) part of the Qi standard or does it use its own? If its Qi then this is a major win!
  • Years ago farmers stole electricity from the power companies using this same concept of charging. Electrical theory 101. As for Tesla, we'd be walking around in insulated suits to prevent from being fried. Great idea but hardly practical.
  • Being a Double E (EE) or "Electrical Energineer" who when to school when transformers played a big roll then computers did I can answer most of your questions on this thread.  the basics is the charging pad is one half of a transformer and the phone or the case has the other smaller coil of wire required to make a stransformer.  Rememger you toys or any device with a big hunking square or metal box between the wall and your device that sometimes hums?  that is the transformer turning the 110V AC out of your wall to a lower AC voltage.  there is a whole lot of math around the number of turns or loops of wire, the thickness of the wire (more Current),  wire type, etc.  so less loops of smaller wire on the device side means less voltage and current are transfered to the output wires. (Why can't I hit RETURN and get a new paragraph?)...  ok so will it work with your touchstone?  Maybe just like it might actually work with our electric toothbrush coil or any other transformer in your house.  if the primary coil found in the touchstone or toothbrush emits enough voltage/current so that the receiving coil in the 920 can pick it up and regulated it (Turn it into DC and preset voltage like 5v or 3.2v or what ever the electronics in the device needs so probably the same voltage level as a USB Port) then it will work.  hec you might be able to get a charge from one of those large green transformers you see around town.  a word of caution! - depending on what sort of over voltage/current protection have been implmented in your device I would be carefull of trying to charge off of large non consumer coils.  I have not read the Qi spec to see what the output voltage is of the coil found in the charger but I am willing to bet it is something lower then 110v AC.  as for building your own,  easy  once you know the Qi specs and understand eletrical enough you could easily make coils of insulated wire (VERY IMPORTANT they be insulated or you might get shock/death!!!)  and slap them under a surface.  if you want to go throught more then 1 inch you need a bigger coil to make a bigger magnetic field but again WARNING big magnetic fields can wipe stuff out like CC, hard drives, etc.  I am thinking the voltage in the Qi spec charger is low enough to not wipe your CC or fry your HD.  Note - Daniel please fix the format or maybe my IE9/windows 8 is messed up :) 
  • Yeah, I also can't do do new paragrahps using Enter key since Windows 8 RP with IE10 came around.
  • It looks like the Qi standard is 5W, I would assume that's what is transferred to the phone (which makes sense since that would be the phone charging at the USB 5V and 1A). If that's the case and the mat only works from a close distance it must provide similar power, since transformers aren't too lossy. Unless, like you mentioned, the phone has some good overvoltage/overcurrent protection.
  • It's Nokia time! :-]
  • I am already all in with the 920. What i am wondering is how well or if it will charge with the phone in it's case. 
  • I think that Nokia needs to make a deal with Starbucks & Barnes and Noble in the US so that they could have greater coverage with another reason to buy that phone. They could have a lil sign on the front windows saying wireless charging with a Nokia Lumis sign..
  • Having worked at Starbucks, I would say having tables with wireless charging would be expensive, if for no other reason than the rewiring that would be needed to supply electricity to the tables. Plus the tables get moved often. The best bet would probably be one special table, or ideally, a counter or shelf. Aside from that I like the idea.
  • This was one of the major reasons why I decided to go with the L920 instead of the 8X.  I plan to get the speaker system that can play music from the phone and charge while sitting on it.  I think it's a pretty cool technology and will evenutally become comon place....every resturant, coffee shop, library will have some form of charging plate in available to customers.
  • ... :o/
    "A wizard does it."
  • I was wondering about the power wastage with wireless charging. Any idea how much power (percentage) it leaks?
  • dumb question...
    what is the SAR rating for the Fatboy Pillow?
  • Any chance the wireless chargers and battery's can be small enough to fit into a belt holster so that your phone is charging while you go about your business?
  • Will the wirless charging still work if you have your phone in a case like an Otterbox defender or commuter?